This invention relates to rotary printing presses and in particular to rotary printing presses which utilize ink pumps to transmit ink to the associated press cylinders.
All rotary printing presses utilize some form of structure to apply printing ink to the plate cylinders which are associated with the printing press. Originally, this structure comprised a fountain roller which was partially immersed and rotated in an ink fountain reservoir. The ink adhered to the surface of the cylinder and was transmitted by various intermediate cylinders to the plate cylinder of the press. With this type of arrangement, it was difficult to control the amount of ink applied to the plate cylinder. Further, it was difficult and time consuming to change the color of ink which was being used by the particular press.
In response to these drawbacks, ink pumps have been designed which utilize a positive displacement pump unit to apply a controlled amount of ink to an associated inking train of the printing press. There are certain drawbacks to those ink pumps which are presently being used. One such drawback is that it is extremely difficult to adjust the individual pumping units of the ink pumps to a position where they do not pump any ink without turning off an associated motor means. This is problematical because generally, multiple pumping units are driven by a single motor means and it is usually desirous to have a certain portion of the pumping units providing ink to the ink tray with a remaining portion being silenced.